Probing Electronic Communications in Heterotrinuclear Fe鈥揜u鈥揊e Molecular Wires Formed by Ruthenium(II) Tetraphenylporphyrin and Isocyanoferrocene or 1,1鈥?Diisocyanoferrocene Ligands

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• 作者：Victor N. Nemykin ; Semyon V. Dudkin ; Mahtab Fathi-Rasekh ; Andrew D. Spaeth ; Hannah M. Rhoda ; Rodion V. Belosludov ; Mikhail V. Barybin
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：November 16, 2015
• 年：2015
• 卷：54
• 期：22
• 页码：10711-10724
• 全文大小：901K
• ISSN：1520-510X

文摘

Two new heterotrinuclear Fe鈥揜u鈥揊e complexes of ruthenium(II) tetraphenylporphyrin axially coordinated with a pair of isocyanoferrocene ((FcNC)₂RuTPP, 1) or 1,1鈥?diisocyanoferrocene (([C₅H₄NC]₂Fe)₂RuTPP, 2) ligands [Fc = ferrocenyl, TPP = 5,10,15,20-tetraphenylporphyrinato(2鈭? anion] were synthesized and characterized by UV鈥搗is, magnetic circular dichroism, NMR, and FTIR spectroscopies as well as by electrospray ionization mass spectrometry and single-crystal X-ray diffraction. Isolation of insoluble polymeric {([C₅H₄NC]₂Fe)RuTPP}_n molecular wires (3) was also achieved for the first time. The redox properties of the new trinuclear complexes 1 and 2 were probed using electrochemical (cyclic voltammetry and differential pulse voltammetry), spectroelectrochemical, and chemical oxidation methods and correlated to those of the bis(tert-butylisocyano)ruthenium(II) tetraphenylporphyrin reference compound, (t-BuNC)₂RuTPP (4). In all cases, the first oxidation process was attributed to the reversible oxidation of the Ru^II center. The second and third reversible oxidation processes in 1 are separated by 鈭?00 mV and were assigned to two single-electron Fe^II/Fe^III couples, suggesting a weak long-range iron鈥搃ron coupling in this complex. Electrochemical data acquired for 2 are complicated by the interaction between the axial 畏¹-1,1鈥?diisocyanoferrocene ligand and the electrode surface as well as by axial ligand dissociation in solution. Spectroelectrochemical and chemical oxidation methods were used to elucidate the spectroscopic signatures of the [1]ⁿ⁺, [2]ⁿ⁺, and [4]ⁿ⁺ species in solution. DFT and time-dependent DFT calculations aided in correlating the spectroscopic and redox properties of complexes 1, 2, and 4 with their electronic structures.